1. Field of the Invention
The present invention relates to a photographic light-sensitive sheet for the color diffusion transfer process and, more particularly, to a silver halide photographic light-sensitive sheet for the color diffusion transfer process which provides a magenta color image whose color reproducibility and hue are improved.
2. Description of the Prior Art
It has been well known in the field of the photographic color diffusion transfer process that using an azo dye image-forming compound which provides an azo dye compound having a different diffusibility from that of the azo dye image-forming compound as a result of development under alkaline conditions, the azo dye compound or the azo dye image-forming compound is subjected to transfer to an image-receiving layer in which a transferred dye image is formed.
Examples of dye image-forming compounds which release magenta dyes are described in U.S. Pat. Nos. 3,932,380 and 3,931,144, etc. However, technical problems are encountered, using these magenta dye releasing dye image-forming compounds specifically described in such prior art, in that the transferred images have insufficient stability. For example, the light fastness of the images is not adequate and the images fade to a large extent even in a dark place. Also, the transfer of the dye compound is not adequate.
For instance, with respect to the fading-in-dark of transferred dye images, it has been known that when a polymer acid (such as polyacrylic acid, a copolymer of acrylic acid and butyl acrylate, etc.), as disclosed in U.S. Pat. No. 3,362,819 hereinafter described, is used in a neutralizing layer, unreacted monomer (such as acrylic acid, butyl acrylate, etc.) remaining in the polymer adversely influences the fading-in-dark of the transferred dye images. It has also been found upon further investigation that unreacted butyl acrylate monomer exceptionally degrades the fading-in-dark of magenta dye images obtained from prior art dye image-forming compounds such as described in U.S. Pat. No. 3,932,380. However, it is extremely difficult from a technical standpoint to limit the amount of unreacted monomer during the synthesis of polymer acid for a neutralizing layer to an extent that it does not adversely influence the fastness of the images. Therefore, it has been desired to develop a dye image-forming compound which releases a dye compound which is less reactive to such a monomer.